ELECTRICAL
AIRPLANE
OPERATIONS
MANUAL
2-05-05
Page
4
Code
01
REVISION 36
AOM-145/1114
DC SYSTEM PROTECTION
The system monitors generators current and voltage to the electrically
supplied equipment to protect it from a control unit failure, such as an
overvoltage or a bus failure. If an overvoltage is detected, the
associated GCU deenergizes the generator, disconnecting it from the
bus.
A bus failure produces an overcurrent condition to one or more
generators. Upon sensing this overcurrent, the GCU isolates the
system networks, opening the BTCs. If any generator remains
overloaded due to the failure, it is then deenergized and disconnected
from the bus.
As long as the generator current exceeds 400 A, a caution message is
presented on the EICAS, indicating that manual load shedding is
required. If no action is taken, the system will be isolated and some
buses may be deenergized.
System protections are designed so that normal transients will not
cause generators to be disconnected from the bus inadvertently.
Resetting of the generator after a failure is accomplished by releasing
the associated Generator Button and then pressing it again.
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